Close Banner

Integrative Health

These Brain Cells May Be Key To Understanding Alzheimer's Progression

Author: Sela Breen

April 09, 2026

Assistant Health Editor

By Sela Breen

Assistant Health Editor

Sela Breen is the Assistant Health Editor at mindbodygreen. She is a graduate of the Medill School of Journalism at Northwestern University, where she studied journalism, international studies, and theatre.

Image by Stocksy | Aleksandar Novoselski

April 09, 2026

Most people have never heard of tanycytes. But these brain cells may hold the key to understanding the progression of Alzheimer's disease.

For decades, scientists have known that the accumulation of the protein tau is a hallmark of Alzheimer's. What they didn't know was how the brain clears tau under normal conditions, and what goes wrong when it doesn't.

A new study published in Cell Press Blue reveals a surprising answer: specialized cells called tanycytes act as a "shuttle system" that transports tau from the brain to the bloodstream. And in people with Alzheimer's, these cells are dysfunctional.

A quick primer on tanycytes & tau

Tanycytes are specialized cells located in the hypothalamus, the brain region that regulates everything from hunger to hormone release. Unlike most brain cells, tanycytes bridge two critical compartments: the cerebrospinal fluid (CSF) that bathes your brain and the blood vessels that connect to the rest of your body.

You can think of tanycytes as gatekeepers with very long arms. Their cell bodies line the walls of the brain, while their arms extend outward until they make direct contact with blood vessels.

Tau is a protein that normally helps stabilize the internal scaffolding of neurons. But in Alzheimer's disease, tau becomes abnormally modified and clumps together into a tangle. Under healthy conditions, tau is cleared from the brain. But in Alzheimer's, this clearance fails, and tau accumulates in the CSF and brain tissue.

Scientists have not been able to answer the question of how tau normally gets out of the brain. But this study may have the answer.

What the research found

According to the research, tanycytes collect tau from the cerebrospinal fluid and release it into blood vessels that eventually drain into the body's main circulation system.

The study demonstrated this using fluorescently labeled tau injected into the brains of mice. Within minutes, the tau appeared inside tanycytes, traveled through their long arms, and was released into the bloodstream.

When the team blocked tanycytic transport in mice, tau levels dropped significantly, showing that the tau wasn't able to get out of the brain efficiently with this passageway blocked. Hindering this transport also negatively effected tau in the hippocampus, the brain region essential for memory.

The researchers took this information and applied to it to humans by examining brain tissue from Alzheimer's patients. They found that tanycytes in Alzheimer's patients' brains were fragmented and disorganized, suggesting their internal structure had broken down. The genes involved in the transport of tau were significantly disrupted in these patients' tanycytes.

To confirm that tau clearance was actually impaired in living patients, the team analyzed data from two cohorts of participants. They found that ratios of tau in the blood and CSF were lower in Alzheimer's patients compared to controls, suggesting that tau wasn't being transported efficiently.

This clearance deficit appeared specific to tau. Other brain proteins showed no difference in their blood-to-CSF ratios between Alzheimer's patients and controls.

Why this matters for Alzheimer's research

This study represents the first time scientists are identifying tanycytes as major players in clearing tau from the brain, which represents a significant shift in how scientists understand Alzheimer's disease.

The issue occuring in the tanycytes of Alzheimer's patients appeared to be disease-specific. When the researchers examined brain tissue from patients with dementia, they found that tanycytes were altered, but not fragmented in the same way.

brain guard+

Sharp. Clear. Focused. Science-backed support for your mind

★ ★ ★ ★ ★

(108)

Shop now

It's important to note that tanycytes have a job beyond clearing tau. They also transport metabolic hormones from the blood into the brain. These hormones have been proposed to play neuroprotective roles in Alzheimer's. If tanycytes are damaged, it could create a double problem: toxic tau can't get out, and protective signals can't get in.

This may help explain the well-documented link between metabolic disorders like obesity and type 2 diabetes and increased Alzheimer's risk.

What this means for you

This discovery won't change your morning routine tomorrow. There's no supplement to boost your tanycytes (yet), and no lifestyle intervention that has been shown to directly protect these cells. But this research is a first step towar